Along the western coast of Southern Thailand, a series of bright tan beaches lines the Andaman Sea. These sandy expanses fill the gaps between the myriad other features touching the sea, from limestone karst towers to mangroves to built-up areas.
The OLI (Operational Land Imager) on Landsat 8 captured these images on March 23, 2026, showing part of the coastal area along Thailand’s Krabi Province. These beaches lie about 50 kilometers (30 miles) east of Phuket across Ao Phangnga, a bay of the Andaman Sea. The beaches are a tourism hotspot and draw visitors from around the world.
Railay Beach and Phra Nang Beach, accessible by boat, are especially a draw for rock climbers who come here to scale the seaside walls of limestone. The towering formations are an iconic part of the region’s tropical karst landscape, resulting from the just-right ingredients of rock type and climate conditions.
Limestone in this region formed from the accumulation of calcium carbonate, the skeletal remains of marine organisms that settled here when the area was covered by a shallow sea hundreds of millions of years ago. Over time, continental collisions lifted the rock upward and shaped it into complex patterns. Rainwater, made slightly acidic due to the tropical environment, assisted in the chemical weathering that eroded the limestone, sculpting the rock into unique shapes.
The karst landscape extends into the sea in the form of islands. For instance, Ko Po Da Nai and Ko Hong, visible in the wide satellite image above, feature st …